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We describe a study of the E–W-trending South Wagad Fault (SWF) complex at the eastern part of the Kachchh Rift Basin (KRB) in Western India. This basin was filled during Late Cretaceous time, and is presently undergoing tectonic inversion. During the late stage of the inversion cycle, all the principal rift faults were reactivated as transpressional strike-slip faults. The SWF complex shows wrench geometry of an anastomosing en échelon fault, where contractional and extensional segments and offsets alternate along the Principal Deformation Zone (PDZ). Geometric analysis of different segments of the SWF shows that several conjugate faults, which are a combination of R synthetic and R’ antithetic, propagate at a short distance along the PDZ and interact, generating significant fault slip partitioning. Surface morphology of the fault zone revealed three deformation zones: a 500 m to 1 km wide single fault zone; a 5–6 km wide double fault zone; and a c. 500 m wide diffuse fault zone. The single fault zone is represented by a higher stress accumulation which is located close to the epicentre of the 2001 Bhuj earthquake of Mw 7.7. The double fault zone represents moderate stress at releasing bends bounded by two fault branches. The diffuse fault zone represents a low-stress zone where several fault branches join together. Our findings are well corroborated with the available geological and seismological data.
Comparative studies have been carried out on the performance of the photovoltaic devices with dissimilar shapes of the InN nanostructures fabricated on p-Si (100). The devices fabricated with the nanodots show a superior performance compared to the devices fabricated with the nanorods. The discussions have been carried out on the superior junction property, larger effective junction area and inherent random pyramidal topographical texture of the cell fabricated with nanodots. Such single junction devices exhibit a promising fill factor and external quantum efficiency of 38% and 27%, respectively, under concentrated AM1.5 illumination.
The effect of silver nanoparticles showing localised plasmonic resonances on the efficiency of thin film silicon solar cells is studied. Silver (Ag) nanodiscs were deposited on the surface of silicon cells grown on highly doped silicon substrates, through hole-mask colloidal lithography, which is a low-cost and bottom-up technique. The cells have no back reflector in order to exclusively study the effect of the front surface on their properties. Cells with nanoparticles were compared with both bare silicon cells and cells with an antireflection coating. We optically observe a resonance showing an absorption increase controllable by the disc radius. We also see an increase in efficiency with respect to bare cells, but we see a decrease in efficiency with respect to cells with an antireflection coating due to losses at wavelengths below the plasmon resonance. As the material properties are not notably affected by the particles deposition, the loss mechanism is an important absorption in the nanoparticles. We confirm this by numerical simulations.
Rabies is a major public health problem in Bangladesh, where most of the population live in rural areas. However, there is little epidemiological information on rabies in rural Bangladesh. This study was conducted in 30 upazilas (subdistricts) covering all six divisions of the country, to determine the levels of rabies and animal bites in Bangladesh. The total population of these upazilas was 6 992 302. A pretested questionnaire was used and data were collected by interviewing the adult members of families. We estimated that in Bangladesh, 166 590 [95% confidence interval (CI) 163 350–170 550] people per year are bitten by an animal. The annual incidence of rabies deaths in Bangladesh was estimated to be 1·40 (95% CI 1·05–1·78)/100 000 population. By extrapolating this, we estimated that 2100 (95% CI 1575–2670) people die annually from rabies in Bangladesh. More than three-quarters of rabies patients died at home. This community-based study provides new information on rabies epidemiology in Bangladesh.
Unprecedented high rates of anthrax outbreaks have been observed recently in cattle and humans in Bangladesh, with 607 human cases in 2010. By enrolling 15 case and 15 control cattle smallholdings in the spatial zone in July–September 2010, we conducted a case-control study, data of which were analysed by matched-pair analysis and multivariable conditional logistic regression. Feeding animals with uprooted and unwashed grass [odds ratio (OR) 41·2, 95% confidence interval (CI) 3·7–458·8, P=0·003], and feeding water hyacinth (Eichhornia crassipes) (OR 22·2, 95% CI 1·2–418·7, P=0·039) were independent risk factors for anthrax in cattle.
Bangladesh faced two epidemic waves of highly pathogenic avian influenza (HPAI) H5N1 in two consecutive years. The peaks of the waves were observed in February–July 2007 and January–April 2008, respectively. We examined the spatial and temporal patterns of the 293 outbreaks in 143 subdistricts in 2007 and 2008. Global clustering assessed by K-function was seen at distances 150–300 km between subdistricts. Significant local clusters were detected by space–time scan statistics. In both waves, significant primary clusters of HPAI outbreaks were identified in the central part of the country dominated by commercial production systems and in the northwestern part primarily in backyard production systems. Secondary clusters varied from the northwestern part in 2007 and the southern part in 2008. The findings are highly relevant for the successful planning and implementation of control, prevention and surveillance strategies by highlighting areas where detailed investigations should be initiated.
Background: Depression in the elderly is a common and disabling condition. The aim of the study was to evaluate the sensitivity and specificity of a two-question screen to identify depression and common mental disorders in the elderly.
Method: Residents of a ward in the town of Vellore were identified by a door-to-door survey from which 204 subjects aged over 60 years were selected for the study by systematic random sampling. They were screened using the two-question screen. The Revised Clinical Interview Schedule (CIS-R) was employed to confirm the diagnosis.
Results: The prevalence of depression and common mental disorder, using the CIS-R standard, was found to be 31.5%. The two-question screen has a sensitivity of 93.8% and specificity of 48.2%.
Conclusions: The high sensitivity of the two-question screen makes it a useful screening method which can be employed by health workers in the field.
This work reports a low-cost method for large scale production of high quality graphene via radio-frequency chemical vapor deposition. High quantities of graphene were successfully synthesized on the Fe-Co/MgO (2.5:2.5:95 wt.%) catalytic system utilizing acetylene as a hydrocarbon source at 1000 °C. The as-produced graphene sheets were purified in a single step by washing with a diluted hydrochloric acid solution under sonication. Next, they were thoroughly characterized by microscopy, spectroscopy, and X-Ray diffraction. Advanced transmission electron microscopy and atomic force microscopy analyses have indicated the formation of 3-5 layered graphene nanosheets. Thorough analyses by Raman spectroscopy were also performed demonstrating the presence of high quality and few-layer graphene samples. This low cost and highly reproducible method may be applied in a straightforward way to produce large quantities of graphene for various advanced applications.
We present a rare and clinically relevant anomaly of the sphenopalatine artery in relation to its blood supply of the nasal mucosa, with implications for the management of epistaxis.
Case report and review of the world literature, using Medline through Pub Med (1950–2005), EMBASE (1980–2005) and Ovid (1958–2005), searching for papers using a combination of terms including ‘spheno-palatine artery’, ‘anterior ethmoidal artery’ and ‘epistaxis’.
In the presented case of refractory epistaxis, endoscopic and subsequent endovascular management failed to identify a significant supply from the sphenopalatine arteries bilaterally. The main supply was found to be from the anterior ethmoidal arteries.
After a detailed search, the authors failed to locate any similar case in the English literature.
This paper presents a systematic formulation for the simulation of rigid body dynamics, including the short period dynamics, inherent to stage separation and jettisoning parts of a satellite launcher. This also gives a review of various types of separations involved in a launch vehicle. The problem is sufficiently large and complex; the methodology involves iterations at successively lower levels of abstraction. The best choice to tackle such problems is to use state-of-the-art programming technique known as object oriented programming. The necessary classes have been identified to represent various entities in the launch vehicle separation process (e.g., gravity, aerodynamics, propulsion and separation mechanisms etc.). Simple linkages are modelled with suitable objects. This approach helps the designer to simulate a launch vehicle separation dynamics and also to analyse separation system performance. To examine the influence of the design variables on the separating bodies, statistical analyses have been performed on the upper stage separation process and pull out of ongoing stage nozzle from the spent stage of a multistage rocket carrier using retro rockets.
We have developed an efficient scheme for simulating silicon nanowires with crystalline cores and amorphous sheaths, using molecular dynamics. By starting with a crystalline nanowire and performing high temperature anneal an amorphous outer sheath can be grown with controlled thickness on the nanowire. Simulations for  nanowires with diameters of 12 nm find low energy facets between the amorphous and crystalline layers. Simulations for  nanowires find weak faceting and an inhomogeneous amorphous-crystalline boundary.
Thin silicon films deposited using the Hot-Wire Chemical Vapor Deposition (HWCVD) technique are studied here for the effect of XeCl excimer laser crystallization on their structural, optoelectronic, and electron field emission properties. Excimer Laser Annealing (ELA) of the silicon thin films indicated increased dark conductivity and reduced optical gap. Encouraging Field Emission (FE) results were obtained from XeCl excimer laser processed HWCVD films on Cr, V, Mo, and Ti backplanes. Geometric field enhancement factors from surface measurements and Fowler-Nordheim Theory (FNT) were compared. FE thresholds were also found to be particularly influenced by the backplane material.
Supercritical fluids (SF) have been used in a wide variety of applications:
in industrial processes, analytical, waste detoxification, etc. Recently,
its usefulness extends to the semiconductor industry. Researches have shown
that supercritical CO2 (SCCO2) can be used to remove
photoresists and significantly reduce the amount of waste from solvents in
comparison to conventional stripping techniques. SF will also find its
usefulness in cleaning high aspect ratio vias and deep trenches as
semiconductor features shrink to submicron levels. We will report here the
use of supercritical CO2 treatments in extraction of porogens
from a nanohybrid film fabricated via templated-porogen approach. Its use as
a medium to repair the damage in porous films from plasma ashing will also
be presented. The ability to tune the solvation and diffusion power of
SCCO2 and to swell the film matrix make it a good medium for
silylation to restore hydrophobicity and functionalize the film.
Food habits of tigers Panthera tigris and population attributes of prey species (population structure, density and biomass) were studied in the tropical dry deciduous forest of Pench National Park, Central India, from November 1998 to April 1999. Scat analysis and line transect method were used to estimate tiger food habits and density of major prey species, respectively. The 61.1 km2 intensive study area was found to have very high ungulate density (90.3 animals km−2) with chital Axis axis being the most common species (80.7 animals km−2), followed by sambar Cervus unicolor (6.1 animals km−2). Common langur Presbytis entellus was the most abundant (77.2 animals km−2) primate species. When the density figures were multiplied by the average weight of each prey species, a high biomass density of 6013.25 kg km−2 was obtained for the intensive study area. Chital (47.3%) along with sambar (14.5%) and wild pig Sus scrofa (10.9%) constituted the major part of the tiger's diet. If there is food choice, tigers seem to kill medium- and large-sized species more often. Wild pig and sambar were consumed more than their availability, whereas chital were taken in proportion to their availability. Gaur Bos gaurus and nilgai Bosephalus tragocamelus were not represented in the tiger's diet. Common langur was consumed in lesser proportion by tigers than expected by estimates of its density. The average weight of animals consumed by tigers in the intensive study area was 82.1 kg. The analyses revealed that Pench harbours very high prey density and tigers are mostly dependent on the wild ungulates rather than on domestic livestock as is the case in many other areas in the Indian subcontinent. These two factors thus make Pench National Park a potential area for long-term conservation of tigers.
Large (11-mm diameter) single-crystal AlN boules have been prepared using sublimationrecondensation growth. X-ray topography shows that substrates prepared from those boules have a dislocation density of less than 500 cm-2, while the central region of these substrates was nearly dislocation-free. Rocking curves of less than 10 arcsecs have been obtained indicating the high quality of these crystals. The AlN substrates have been used to growth an AlGaN/AlN multiquantum well structure with excellent crystalline quality and with photoluminescence peaked at around 260nm. In addition, a UV LED with emission wavelength at 360nm has been fabricated. This is the first operating opto-electronic device demonstrated on an AlN substrate.
Composite coatings containing quasicrystalline (QC) phases in Al-Cu-Fe alloys were prepared by laser cladding using a mixture of the elemental powders. Two substrates, namely pure aluminum and an Al-Si alloy were used. The clad layers were remelted at different scanning velocities to alter the growth conditions of different phases. The process parameters were optimized to produce quasicrystalline phases. The evolution of the microstructure in the coating layer was characterized by detailed microstructural investigation. The results indicate presence of quasicrystals in the aluminum substrate. However, only approximant phase could be observed in the substrate of Al-Si alloys. It is shown that there is a significant transport of Si atoms from the substrate to the clad layer during the cladding and remelting process. The hardness profiles of coatings on aluminum substrate indicate a very high hardness. The coating on Al-Si alloy, on the other hand, is ductile and soft. The fracture toughness of the hard coating on aluminum was obtained by nano-indentation technique. The K1C value was found to be 1.33 MPa m1/2 which is typical of brittle materials.
Variation of hardness with penetration in nanoindentation of a rough surface is a compound effect of variation in asperity geometry with penetration, designated geometric effect, and genuine property gradients with depth as may exist in a near-surface zone. We simulate indentation of a rough surface numerically to elucidate the geometric effects and validate it by some model “macro” experiments. Finally, we formulate a general framework to deconvolute genuine property variation by normalizing the measured hardness with the geometric effect.
The roughness of metallic surfaces generated by machining depends on the intended intervention by the tool and the inadvertent consequences determined by the response of metals. The roughness generated in four different metals by grinding is studied using the power spectrum method. It was found that the level of power is determined by the intended intervention such as the depth of cut and, to some extent, by hardness because of its possible influence on micropileup geometry. The power gradient is, however, influenced by inadvertent damage which may be related to material properties such as thermal conductivity and adhesion.
We report here the remarkable abrasion wear resistance (normal pressure: 2.92 to 5.42 MPa; sliding speed: 0.25 to 3 m/s) of a soft (relative to other structural ceramics) melt-oxidized ceramic matrix composite Al2O3 –SiC–(Al, Si). In spite of being half as hard and more porous than zirconia toughened alumina (ZTA), a common cutting tool material, this composite fabricated at 1100 °C shows wear resistance comparable to that of ZTA at sliding speeds more than 2 m/s. The ability of this composite to generate a metal-rich tribofilm when rubbed and its high thermal shock resistance are factors which may be responsible for this unique performance.